Since organic electroluminescent elements (which may hereinafter also be referred to as “elements” or “organic EL elements”) are capable of high-luminance light emitting using low voltage driving, they have been actively researched and developed. The organic electroluminescent elements have organic layers between a pair of electrodes, and utilize, for light emitting, energy of the exciton generated as a result of recombination of electrons injected from a cathode and holes injected from an anode in the organic layer.
Recently, by using phosphorescent light emitting materials such as an iridium complex, the efficiency of the elements is increasingly increased (see PTLs 1 to 4).
However, elements using iridium complexes in the related art need to be further improved from the viewpoint of durability.